Power-generating system having air heater



Jan. 24, 1928. 1,656,985

w. s. MONROE POWER GENERATING SYSTM HAVING AIR HEATER Filed March io,1923 02 il 0 N cn m 111 n lim (I3 n rox] u @"g i?) ATTORNEYS. v

ltatented dan. Zei, 1925.

UhllTlilD STATES:

PATENT OFFICE.

'WILLIAM S. MONROE, OF (LI-IIL'JACw'rO,` ILLINOIS;

application site Maren 10,1923. serial No. 624,080.

My present invention relates to systems for generating power in whichsteam from steam` generators is supplied to a multi-'stage prime moverandin which some ofthe exhaust from one or more stages of such` primemover is withdrawn fromjthe prime mover and the heaty thereof returnedto the system.

My present invention will be best understood from the followingdescription and the annexed drawing; in which I have showndiagrammatically one embodiment.

In this illustrative embodiment, 10 is a steam boiler having aforced-blast stolzer 11 and a superheater 12 from which steam issupplied through a pipe 13 to the highpressure stage of a multi-stagesteam turbine iet connected to a generator 15. The boiler is providedwith an economizer 16 over which the gases flow downward from the boiler10, and from thence to thestack 17.

The condenser 18 receives the exhaust from the turbine le and thecondensate passes through the pipe 19 into a feed-water and air-heatingsystem to be described more fully hereinafter7 the pump 20 forcing thiscondensate into the system, and a feed pump 21 withdrawing the feed.water from the system and forcing it through thepipe 22 into theeconomizer 16 from which it passes into the boiler 10 in the usualmanner.

The system referred to comprises the `heaters 23, 24 and 25, the heater28 being supplied through the pipe 26 with steam from between a pair ofrelatively low-pressure stages of the turbine, the heater 2e beingsupplied through the pipe 2'? with steam from between a pair of stagesat a relatively higher pressure, and the heater beingl supplied throughthe pipe 28 with steam from the steam packing gland of the turbine.These heaters 23, y2d and 25 are connected by pipes 29, 8O and 31 withthe condensate pump 20 and with each other, so that these heaters are inseries in the direction of flow of the water therethrough, the pipe 82connecting the last heater .with the feed pump 21.

A duct 83 connected to a forced-draft fan 8d supplies air to the fuel onthe grate 11. rIhis air passes over heating surfaces in an air heater85, these heating surfaces being supplied rvith hot water from theheater 25 through a pipe 36, the water after passing through the airheater, returning through a pipe 37 to a pump 38 which is connected tothe pipe 29.

By l way of illustration, but without intending to be limited to thespecilic arrangementor figures, the operation of my system may bedescribed as` follows:

The steam passing through the pipe 26 mayhave a temperature of, say,150O F. The condensate, therefore,` will first be heated toapproximately that temperature and will then flow to the second heater24, where it will be heatedv by steam at a temperature of, say, 200o F.From the heater 24, it will flow to the heater 25, where it is heated bysteam which may have a temperature of, say, 212. From the heater 25,sufficient water will be drawn by the pump 2l to feed the boiler. Thepump 38 acting with the pump 20, will cause the remaining water in thesystem to circulate throughv the air heater to heat the air passing tothe grate 11. It will thus be seen that the steam drawn from theintermediate stages of the turbine will be utilized not only to heat thefeed waterl to the desired temperature, but will also heat thecombustion air and that the quantity of steam which may thus be drawnoff from the turbine is not limited to the amount required to heat thefeed water to the desired temperature. Indeed, it will be noted that`the system including the heaters23, 2d, 2 5, air' heater 35 and thecirculating pump 88, constitu-te what is, in edect, a closed system sofar as the air heater is concerned, in which the circulating waterserves to transfer the heat from the steam withdrawn' from the turbineto the combustion air, though I nd it advan tageous to use this systemalso to heat the feed water in the manner which I have described.

Nhile I have shown three heaters supplied with steam from the turbine,it will be understood that any number may be used though I lind itadvantageous to use a plurality in the manner illust-rated, in orderthat the temperature of the water may be increased progressively as itflows through the several heaters. Preferably, the air heater will beof'such size that though it receives water, say, at a temperature of 212F. from the heater 25, the water passing therefrom will be reduced to atemperature of, say, from to 80 I?. or approximately that of thecondensate from the condenser 18.

It will be understood that the arrangement which I have used forpurposes of illustration may be widely varied and that I do not wish tobe .limited to the speeilic form which I have shown.

l claim:

l. In a power-generatinel system, a steam boiler' having a furnace, amulti-stage prime mover supplied with steam trom said boiler, an airheatel' arranged to transfer heat 'troni water lo air, means to passcombustion air through said air heater to the furnace, awater-circulating s stein connected to said air heater and hai/ing aheatsexchanger therein, connections to supply steam trom anintermculiate stage oi the prime mover to said l1eate:;changer and apump in said wateneirculating system, whereby the "water may becircula-ted through the air heater and the heat exchanger at any desiredrate.

2. ln a poWeiener-aLing;` system, a steam boiler ha ring;` a furnace, amulti-stage prime mover supplied with steam trom said boiler, an airheater arranged to transfer heat `from water to air, means to passcombustion air through said air heater to the furnace, awater-eireulating system connected tiosaid air heater' and havingr aheat-exchanger therein, connections to supply steam from an intermediatestage ot the prime mover to said heat-etchanger, and connections betweensaid wtiter-circulating s; stem and said boiler to supply feed Watertroni the system to the boiler.

3. In a power-generaling s yictenl, a steam boiler havingl a furnace, amultistage, prime mover supplied with steam i'rom said boiler, an airheater arranged to transfer' heat from Water to air, ineens to passcombustion air through said air heater to the furnace, au'uter-eirculatini; system connected to Said air heater and hating aplurality7 ot heaters therein, a eonneeti on between each heater in theWater Circulating system and the exhaust outlettrom an interlinediatestage ot the prime mover arranged to supply steam at progressivelyhigher temperatures to the Water which lf'lows to the air heater and a`pump :in said water-circulating system, whereby the water may becirelilated through the air heater and the heaters at any desired rate.

il. In :r power-generating sistem, a steam boiler ha ringe furnace, alimiti-etage prime mover supplied with steam from said boiler, an airheate arranged to transiter heat from water to air, means to passcombustion air through said air heater to the turuace, a'u'ater-circulating system connected. to said air heater and haring :iplurality oi. heaters therein, a connection between each heater in thewater circulatingl system and a pair et intermediate stages oil. theprime mover arranged to supply steam at progressively highertemperatures to the water as it lows toward the air heater, and aconnection bew tween the last heute' and the boiler to supl'eed water tothe boiler. Y, ln a power-generating system, a steam boiler lravingg afurnace, a .multhstage prime mover supplied with steam :troni saidboiler and hari a condenser for the exhaust steam therefrom, an airheater arranged to trans `ler heat from water to air, means to passcoinlmstion air through said air heater to the furnace, awater-circulating system connected to said air heater and haring;r uheater therein, connections to euiiply steam from an intermediate stageol the prime mover to said Water heater, a connection and a pump betweenthe exhaust steam condenser and said watereirculating system, and uconnection and a pump between the Watencircu latine' system and theboiler, said wateren'- culating system having a pump therein, wherebythe water in the system may be circulated through the heater and the airheater at any desired rate, independently of the suppl;T ol condensateor the ai'nount of teed Water required by the boiler.

WM. S. MONRU E.

